1. Challenges to sensor- based N-Management for Cotton E.M. Barnes 1, T. Sharp 2, J. Wilkerson 3, Randy Taylor 2, Stacy Worley 3 1 Cotton Incorporated, Cary NC 2 Oklahoma State University, Okmulgee & Stillwater 3 University of Tennessee, Knoxville

2. Acknowledgements Tom Clarke, Glenn Fitzgerald, P. Pinter  USDA, ARS, Arid Land Research Center  Maricopa, AZ Pete Waller, University of Arizona  Paul Colaizzi, USDA, ARS – Lubbock, TX  Julio Haberland – Chile  Mike Kostrzewski - Arizona

3. Outline Cotton 101 Why cotton interest in sensors is high The challenges of Cotton One proposed solution

4. Cotton 101

5. Data from USDA, NASS The Cotton Belt

6. Cotton & Nitrogen Perennial plant managed as an annual  Indeterminate flowering pattern ~50 lbs-N per lint bale (1 bale = 480 lbs) Over-application of N:  Energy partition to vegetative vs. reproductive development  Large plants prevent efficient harvest  Growth regulators applied to control vegetative development

7. Why interest in sensors now? Cost of N Producers receiving In-Time images  And now Deere imagery through Jimmy Sanders On-farm tests done in Alabama to use GreenSeeker TM to apply growth regulator (PIX) Cotton researchers joining in

8. 2 3 4 6 1 Lowest Biomass 7 Highest Biomass 5 5.0 gpa 6.0 gpa 7.0 gpa 8.0 gpa 4.5 gpa, 24 fl. oz Prep, 1.5 dry oz Dropp 8.0 gpa, 42.67 fl. oz Prep, 2.67 dry oz Dropp 8.0 gpa Location: Arkansas Delta Crop: Cotton Field Size: 339.5 Acres Imagery Acquired: September 7, 2004 VR Defoliation Applied: September 14, 2004 Notes: This prescription was applied using a hydraulic aerial VR system. The consultant was able to achieve a one-time defoliation on this field, for $15.94/A in chemical. Variable Rate Defoliation

9. Variable Rate Nitrogen Top-Dressing 2 3 4 6 1 Lowest Biomass 7 Highest Biomass 5 0 lbs./A 100 lbs./A 0 lbs./A 100 lbs./A Location: Arkansas Delta Crop: Cotton Field Size: 156.53 A’s Imagery Acquired: July 5, 2004 VR Fertilizer Applied: July 13, 2004 Notes: This prescription was applied using a variable rate equipped high clearance spreader. Unity [16% nitrogen (N)] was applied midseason, to supplement areas in the field which had become N deficient. Classes 1 and 2 were beyond salvaging with the additional N, while classes 6 and 7 required no additional N.

10. Challenges

11. Wind blows & Index Changes + Heliotropic; + New Growth

12. Sample data set 1999 Growing season AGIIS sensor (calibration panel every minute) Water and Nitrogen treatments

13. 1999 CCCI (relative to WN) Last N Application Squares Green BollOpen Boll

14. Yield = -m*NDVI + C ?

15. Possible solution?

16. Combining Data Use NDVI / Greenseeker as a “biomass” sensor Historic yield maps.

17. Concept

18. Application

19. Theoretical Example

20. Combined

21. Conclusions Cotton can be tricky to manage Efforts to apply sensors for N management are increasing rapidly Hope to learn from work here most efficient methods to develop cotton N management strategies

22. AgIIS (Agricultural Irrigation Imaging System) Bands (nm): Green (555), Red (670), Edge (720), NIR (790) IRT

23. Field during 1999 Cotton Season October 1, 1999 AgIIS

24. CCCI CCCI = (C-B)/(A-B) B C A

25. 1999 RVI (relative to WN) Last N Application Squares Green BollOpen Boll